1. Field of the Invention
The present invention relates to a mobile telephone equipped with a casing of a battery lid or a two-piece case.
2. Description of the Related Art
Mobile electronic device is disclosed in Japanese Patent No. 3915332 where a substantially semicircular notch is provided at an end of a battery lid. The battery lid can then be attached to and detached from the casing by using a circular lock knob at this notch. Mobile electronic device where the battery lid is fixed more reliably to the casing as a result of locking using a plurality (two) of such lock knobs at the notch of the end of the battery lid is disclosed in, for example, Unexamined Japanese Patent Application KOKAT Publication No. 2007-312255. Further, with this electronic device, the casing can also be split at substantially the middle into two pieces of an upper and lower casing (for example, refer to Unexamined Japanese Patent Application KOKAI Publication No. 2001-321215).
However, it is also necessary to provide a lock knob and to make a locking lug that engages with a locking piece provided at an inner periphery of the substantially semicircular notch of the end of the battery lid large. This is in order to ensure that the battery lid provided with the substantially semicircular notch at an end portion is reliably fixed to the casing and is disclosed in Japanese Patent No. 3915332. As disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2007-312255, fixing of the battery lid to the casing at the time of locking is stable at the notch of the end portion of the battery lid for mobile electronic device employing a number of lock knobs compared to using only one lock knob. However, more reliable fixing is desired. As disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2001-321215, reinforcing countermeasures such as the providing of an internal metal case is needed in a casing constructed of upper and lower casings that split at substantially the center, because of the difficulty to dissipate an impact, such as from dropping, to the upper and lower casings.